Digital cellular land mobile telecommunication systems
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- 1.1 Authentication centre (AUC)
- 1.2 Base station (BS) The BS is the common name for all the radio equipment at one location, used for serving one or several cells. 1.3 Home location register (HLR)
- 1.6 Mobile services switching centre (MSC)
- 1.7 Short message entity (SME)
- 2.1 Intersystem handoff (handover)
1 Functional overviewThis section provides a description of the services requiring intersystem operations and presents a network reference model that shows the functional entities of a wireless system. A wireless network is comprised of several functional entities and associated interface reference points. Communication among the entities to support functions relevant to a network is performed through a specified set of messages and protocols. The TIA/EIA IS-41 Intersystem Operations Standard provides the messages, protocols, and procedures to facilitate communication between the logical functional entities of a wireless system for the purposes of automatic roaming and call handoff. The entities comprising a cellular network are depicted in Fig. 15.
FIGURE 15 [1073-15]= 15 CM 1.2 Base station (BS)The BS is the common name for all the radio equipment at one location, used for serving one or several cells. 1.3 Home location register (HLR)The HLR is the location register where a user identity and associated subscriber information (e.g. ESN, DN, profile information, current location, validation period) is stored. The HLR may, or may not be located within, and be indistinguishable from an MSC. A HLR may serve more than one MSC. The HLR may be distributed over more than one physical entity. 1.4 Message centre (MC)The MC is responsible for managing short message service features, storing and forwarding of short messages, and delivering short messages to MS based SMEs. 1.5 Mobile station (MS)The MS is the interface equipment used to terminate the radio path at the user side. It provides the capabilities to access network services by the user. 1.6 Mobile services switching centre (MSC)The MSC is an automatic system which constitutes the interface for user traffic between the cellular network and other public switched networks, or other MSCs in the same or other cellular networks. As used in this Appendix, the term “traffic” refers to information conveyed to, or from the user, as opposed to information involving the management of the network. MSCs can take on different roles as: Anchor MSC: the first MSC of radio contact in a call. Border MSC: an MSC controlling cells adjacent to the location of a mobile station. Candidate MSC: an MSC which could possibly accept a call for handoff. Originating MSC: the MSC detecting an incoming call toward a mobile station. Remote MSC: the MSC at the other end of an intersystem handoff trunk. Serving MSC: the MSC currently providing service to a call. Tandem MSC: an MSC providing only trunk connections for a handed off call. Target MSC: the MSC selected for a handoff. Visited MSC: an MSC providing service to the mobile station. 1.7 Short message entity (SME)The SME is an entity which is responsible for the composition and disposition of short messages delivered through the message centre. 1.8 Visitor location register (VLR)The VLR is the location register other than the HLR used by an MSC to retrieve information for handling of calls to or from a visiting subscriber. The VLR may, or may not be located within, and be indistinguishable from an MSC. The VLR may serve more than one MSC. 2 Intersystem servicesServices requiring intersystem operations include: – intersystem handoff (Handover), – automatic roaming, – authentication and privacy, – intelligent networking, – short message services, – operations and maintenance.
A handoff process is triggered when the system serving a MS determines, through a signal measurement process (e.g., intersystem signal measurements or a mobile assisted handoff), that the MS should handoff to a target cell. The handoff occurs when the MS is instructed to re-tune to a specified channel on the target cell. The IS-41 handoff functionality is provided through a series of basic operations which include: – FacilitiesDirective – Used to request the target MSC (recipient) to initiate a handoff forward task. – FacilitiesRelease – Used to request all allocated resources for a call segment to be released. – FlashRequest – Used to inform the anchor MSC that a flash was received from the specified MS. – HandoffBack – Used to request the target MSC (recipient) to initiate a handoff backward task. – HandoffMeasurementRequest – Used by the serving MSC to request a neighbouring MSC to perform a signal quality measurement on a specified traffic channel. – HandoffToThird – Used by the serving MSC to initiate a handoff with path minimization. – InformationForward – Used after handoff to transfer information concerning the served MS toward the serving MSC. – InterSystemAnswer – Used after handoff to inform a border MSC that the called party has answered. – MobileOnChannel – Used by the target MSC to confirm the arrival of the MS on the new traffic channel. Directory: dms pubrec -> itu-r -> rec rec -> Recommendation itu-r bt. 1833-2 (08/2012) rec -> Rec. Itu-r p. 681-6 rec -> Recommendation itu-r m. 585-3 Assignment and use of maritime mobile service identities rec -> Rec. Itu-r ra. 611-3 rec -> Recommendation itu-r f. 383-9 (02/2013) rec -> Recommendation itu-r m. 1801-2 (02/2013) rec -> Rec. Itu-r sm. 1132-2 rec -> Recommendation itu-r m. 1459 (05/2000) rec -> Recommendation itu-r sa. 515-4 Frequency bands and bandwidths used for satellite passive sensing rec -> Recommendation itu-r bs. 1738-1 (10/2015) Download 0.5 Mb. Share with your friends:
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